Conventionally, a number of steel structures and concrete structures have been built at the sea, beach, river, lake, and the like, and they are always exposed to a severe corrosive environment. As a conventional technique for repairing the wet surfaces of these structures, one which is conducted by intercepting water at the surroundings and discharging the water and drying the surfaces is known, but this technique needs a very high cost of the operations.
Therefore, there have been provided corrosion-resistant materials of a wet surface coating type, which can be applied and cured without completely drying the surface, and which have a polyamide curing epoxy resin, a modified amine curing epoxy resin, an unsaturated polyester resin, or the like as a base material (see, for example, PTL's 1 and 2).
However, the coating materials of a wet surface coating type having the above-mentioned resin as a base material have problems in that the application properties with respect to the wet surface of concrete are insufficient, and in that, even when the composition can be applied to the wet surface of concrete, the formed film has only insufficient adhesion to the surface.
In recent years, from the viewpoint of the life of large-size structures, demands of repairing the concrete having cracks and making the concrete aseismatic are increasing, and however, particularly with respect to the difficult application such as in tunnels having spring water and hot spring places which are highly acidic, a conventionally provided coating material of a wet surface coating type frequently cannot meet the demands, and an improvement of the performance of the coating material is desired.